渗透膜结晶法结晶木瓜蛋白酶

Study on osmotic membrane crystallization of papain

用中空纤维微孔疏水膜进行木瓜蛋白酶的渗透膜结晶，研究温度和不同pH的缓冲溶液对木瓜蛋白酶静态渗透膜结晶的影响，优化木瓜蛋白酶渗透膜结晶的结晶条件．通过监控结晶溶液中木瓜蛋白酶浓度随时间的变化，考察沉淀剂和添加剂对结晶过程的影响，并对晶体进行尺寸分布分析．结果表明，对于木瓜蛋白酶的渗透膜结晶，在15～32℃下，以pH4．7的乙酸盐为缓冲溶液，在沉淀剂（硫酸铵和磷酸钠）质量分数4％时，制备出质量较好的木瓜蛋白酶晶体．添加剂PEG600和PEG4000的加入提高了溶剂跨膜通量，改善了晶体质量．

The static osmotic membrane crystallization of papain was studied, and optimal crystallization conditions were chosen. The influences of temperature and buffers with various pH levels on the static osmotic membrane crystallization of papain were studied. The changes of papain concentration with time in crystallization solutions were monitored, and the influences of precipitants and additives on crystallization process were also investigated. Finally, the crystal size distribution was analyzed. The results showed that, for the osmotic membrane crystallization of papain, when 0.1 mol/L sodium acetate solution at pH 4.7 was used as buffer, and temperature was in the range of 15-32 ℃, protein crystals with good quality were obtained under mass fraction 4% precipitants （（NH4）2SO4 and Na3PO4）. Additives such as PEG600 and PEG4000 can enhance greatly transmembrane flux and improve the quality of crystals.